Coupling of $t\bar t$ and $\gamma\gamma$ with a strongly interacting Electroweak Symmetry Breaking Sector

TL;DR

This paper models the coupling of external gamma-gamma and top-antitop states to a strongly interacting electroweak symmetry breaking sector using unitarization and perturbation theory, predicting potential resonances observable at the LHC.

Contribution

It introduces a modified IAM unitarization method to analyze the strongly interacting EWSBS coupled with external states at NLO in a nonlinear effective field theory.

Findings

Describes resonances in the electroweak sector relevant for LHC searches.

Provides a framework to predict effects on gamma-gamma and t-tbar channels.

Models couplings consistent with unitarity and perturbation theory.

Abstract

We report the coupling of an external $\gamma\gamma$ or $t\bar t$ state to a strongly interacting EWSBS satisfying unitarity. We exploit perturbation theory for those coupling of the external state, whereas the EWSBS is taken as strongly interacting. We use a modified version of the IAM unitarization procedure to model such a strongly interacting regime. The matrix elements $V_LV_L\to V_LV_L$, $V_LV_L\leftrightarrow hh$, $hh\to hh$, $V_LV_L\leftrightarrow\{\gamma\gamma,t\bar t\}$, and $hh\leftrightarrow\{\gamma\gamma,t\bar t\}$ are all computed to NLO in perturbation theory with the Nonlinear Effective Field Theory of the EWSBS, within the Equivalence Theorem. This allows us to describe resonances of the electroweak sector that may be found at the LHC and their effect on other channels such as $\gamma\gamma$ or $t\bar t$ where they may be discovered.